A Novel Apparatus to Standardise the Polishing Protocol to Achieve Different Roughness of Titanium and Zirconia Disc Surfaces.

PURPOSE: This study aimed to propose and evaluate standardised polishing protocols for in vitro experiment using a custom-made apparatus under controlled force to create consistent surface roughness on titanium and zirconia disks. METHODS: A total of 160 discs were manufactured with a diameter of 10mm, 80 titanium (Ti), and 80 zirconium oxide (Zr). Specimens were categorised into 2 groups: controlled force (CF) and without controlled force (WCF). Specimens in the CF group were polished with a custom apparatus incorporating a tension gauge on the Ti and Zr disc surfaces to achieve consistent roughness. The WCF was polished without the use of a tension gauge. Each group had 4 subgroups (10 disks in each): control/machined (C) with no polishing, rough (R), smooth (S) and very smooth (VS). The subgroups were processed using a sequence of diamond-impregnated polishing burs and polishing paste. RESULTS: CF group showed consistent surface roughness and a gradual decrease in surface roughness. Control (Ra=6.5±0.03µm) in Ti and (Ra=5.4±0.04µm) in Zr; R (Ra=3.5± 0.06µm) in Ti and (Ra=3.2± 0.07 µm) in Zr; S (Ra=1.5±0.04µm) in Ti and (Ra=1.1±006µm) in Zr; VS (Ra=0.05± 0.002µm) in Ti and (Ra=0.02±0.005µm) in Zr. There were significant differences for R, S, and SV under CF and WCF in Ti and Zr surfaces. CONCLUSION: The specimens polished under control force produced significantly more uniform surface roughness than those polished without controlled force and were produced with a higher degree of consistency.

The Resolution of Periodontal Inflammation Promotes Changes in Cytokine Expression in the Intestine and Gingival Tissues of Aged Rats with DSS-Induced Colitis.

Our research aimed to explore how resolving periodontal inflammation impacts cytokine expression in the colons of aged Wistar rats. Research studies involving animals have been conducted to investigate the two-way relationship between periodontitis and inflammatory bowel disease (IBD), where chronic inflammation in either the mouth or intestines can negatively affect the other. We allocated seventeen male Wistar rats aged between 8 and 11 months to one of four groups: (1) ligature-induced periodontitis (LIP) without the resolution of periodontal inflammation (RPI) (LIP; n = 4), (2) LIP + RPI (n = 4), (3) LIP + dextran-sulphate-sodium-induced colitis (DIC) without RPI (n = 4), and LIP + DIC + RPI (n = 5). We performed histopathological and immunological analyses on periodontal and intestinal tissues and analysed cytokine expressions using a Rat Cytokine 23-Plex Immunoassay. Our findings showed that animals with and without DIC who underwent RPI showed significantly lower levels of IL-2, IL-4, IL-5, IL-10, IL-13, IL-17, IL-18, and TNF-α in the intestine compared to those without treatment. The RPI effectively reduced the number of inflammatory cells in the lamina propria and restored the epithelial barrier in the intestine in animals with DIC. The resolution of periodontal inflammation significantly reduced the levels of pro-inflammatory cytokines and chemokines in the intestines of aged rats with and without DSS-induced colitis.

Higher expression of Th1/Th2-related cytokines in the intestine of Wistar rats with ligature-induced periodontitis.

OBJECTIVE: This study aimed to investigate the impact of ligature-induced periodontitis (LIP) on histopathological and immunological outcomes in the colon of Wistar rats. BACKGROUND: It has been repeatedly shown that inflammatory bowel disease (IBD) patients are at higher risk of developing periodontitis and presenting worse oral health than non-IBD patients. However, whether the chronic inflammatory process around teeth contributes to the pathophysiology of IBD needs to be further explored. MATERIALS AND METHODS: Thirteen Wistar rats were allocated into LIP (n = 7) and controls (n = 6). Half of the colon was processed for histopathological analyses and immunohistochemical (CD45); the other half was homogenized for immunological analyses. Periodontal destruction was confirmed by measuring the distance from the cementum-enamel junction to the mandible's apical position of the mesial interproximal bone. The immunological analyses were performed with the Bio-Plex Th1/Th2 assay. RESULTS: There was a significantly higher interproximal bone loss in LIP compared to controls. The LIP group showed a moderate infiltrate of inflammatory cells, predominantly mononucleated cells in the intestinal tissues. There was significantly higher expression of GM-CSF, IFN-γ, IL-1α, IL-1ß, IL-2, IL-4, IL-5, IL-10, IL-12 (p70), IL-13, and TNF-α in the intestinal tissues of LIP group compared to controls. CONCLUSION: Ligature-induced periodontitis was associated with an overexpression of Th1/Th2-related cytokines in the colon of Wistar rats.

Colitis induced by dextran sulphate sodium causes histopathological and immunological changes in the periodontal tissues of Wistar rats.

OBJECTIVE: This study investigated the impact of colitis induced by dextran sulphate sodium (DSS)-induced colitis (DIC) on histopathological and immunological outcomes in the periodontal tissues of Wistar rats. BACKGROUND: Inflammatory bowel diseases (IBD) and periodontitis have been reported to present a bidirectional relationship. However, the inflammatory pathway that connects both diseases needs further investigation. MATERIAL AND METHODS: Twenty-five male Wistar rats were allocated in four groups: unilateral ligature-induced periodontitis for 14 days: LIP (n = 7); dextran sulphate sodium-induced colitis only: DIC (n = 6); DIC + LIP (n = 6) and controls (n = 6). Digital images were obtained from the histological sections. In order to assess the attachment loss (AL), the linear distance between the cementoenamel junction (CEJ) and the alveolar bone crest was measured on the mesial root using histological photomicrography's ImageJ software. Immunological analyses of gingival tissues and plasma were performed by Bio-Plex Th1/Th2 Assay. RESULTS: The DIC group showed inflammatory cells extending to the periodontal connective tissues, which contained significantly elevated expressions of IL-1α, IL-1ß, IL-2, IL-6, IL-12, IL-13, GM-CSF, IFN-γ and TNF-α compared to controls. There was no significant difference in bone loss between controls and DIC. There were no significant histopathological differences between DIC + LIP and LIP. However, DIC + LIP presented a significantly lower IL-2 and IL-5 than the LIP group. There was no bone loss difference between LIP+DIC and LIP groups. DIC + LIP group presented significantly higher levels of GM-CSF in plasma. CONCLUSION: DSS-induced colitis was associated with an overexpression of Th1/Th2- related cytokines in the gingival tissue.

A systematic review on neutrophils interactions with titanium and zirconia surfaces: Evidence from in vitro studies.

OBJECTIVES: This systematic review aimed to assess in vitro studies that evaluated neutrophil interactions with different roughness levels in titanium and zirconia implant surfaces. MATERIAL AND METHODS: An electronic search for literature was conducted on PubMed, Embase, Scopus, and Web of Science and a total of 14 studies were included. Neutrophil responses were assessed based on adhesion, cell number, surface coverage, cell structure, cytokine secretion, reactive oxygen species (ROS) production, neutrophil activation, receptor expression, and neutrophil extracellular traps (NETs) release. The method of assessing the risk of bias was done using the toxicological data reliability assessment tool (TOXRTOOL). RESULTS: Ten studies have identified a significant increase in neutrophil functions, such as surface coverage, cell adhesion, ROS production, and NETs released when interacting with rough titanium surfaces. Moreover, neutrophil interaction with rough-hydrophilic surfaces seems to produce less proinflammatory cytokines and ROS when compared to naive smooth and rough titanium surfaces. Regarding membrane receptor expression, two studies have reported that the FcγIII receptor (CD16) is responsible for initial neutrophil adhesion to hydrophilic titanium surfaces. Only one study compared neutrophil interaction with titanium alloy and zirconia toughened alumina surfaces and reported no significant differences in neutrophil cell count, activation, receptor expression, and death. CONCLUSIONS: There are not enough studies to conclude neutrophil interactions with titanium and zirconia surfaces. However, different topographic modifications such as roughness and hydrophilicity might influence neutrophil interactions with titanium implant surfaces.

Peri-Implant Surgical Treatment Downregulates the Expression of sTREM-1 and MMP-8 in Patients with Peri-Implantitis: A Prospective Study.

sTREM-1 and its ligand PGLYRP1 play an essential role in the inflammatory process around teeth and implants. In this study, we aimed to evaluate the impact of peri-implant treatment on the salivary levels of the sTREM-1/PGLYRP-1/MMP-8 axis after 3 months. A total of 42 participants (with a mean age of 61 years old ± 7.3) were enrolled in this longitudinal study, 24 having peri-implant mucositis (MU) and 18 having peri-implantitis (PI). Clinical peri-implant parameters, such as probing pocket depth (PPD), % of plaque, and bleeding on probing (BOP), and the whole unstimulated saliva samples were evaluated at baseline and 3 months after treatment. The MU group received nonsurgical peri-implant treatment, while the PI group received open-flap procedures. The levels of sTREM-1, PGLYRP-1, MMP-8, and TIMP-1 were analyzed using enzyme-linked immunosorbent assays. BOP, plaque levels, and PPD significantly reduced after treatment in both groups. A significant decrease in the salivary levels of sTREM-1, MMP-8, and TIMP-1 in the PI group and PGLYRP1 and TIMP-1 in the MU group were observed. Salivary levels of sTREM-1 were significantly reduced in patients with PI but not with MU. Additionally, peri-implant treatment had a significantly higher impact on MMP-8 reduction in patients with PI than in those with MU.